Figure 2.

Images obtained by atomic force microscopy. Morphological changes could be observed in all bleached groups compared to the control (a), regardless of the thickener used (b) (carbamide peroxide + carbopol), (c) (carbamide peroxide + carbopol + glycerin), and (d) (carbamide peroxide + natrosol)). However, carbamide peroxide + natrosol (d) presented a less pronounced surface alteration when compared with carbamide peroxide + carbopol (b), as demonstrated by the smaller difference in peak-valley measurements on the enamel surface